Composite materials offer potential design improvements in gas turbine engines. For example, in recent years composite materials have been replacing metals in gas turbine engine fan blades because of their high strength and low weight. Most metal gas turbine engine fan blades are titanium. The ductility of titanium fan blades enables the fan to ingest a bird and remain operable or be safely shut down. The same requirements are present for composite fan blades.
A composite fan blade can have a sandwich construction with a three-dimensional woven core at the center and two-dimensional filament reinforced plies or laminations on either side. To form the composite blade, individual two-dimensional laminations are cut and stacked in a mold with the woven core. The woven core extends from the root to the tip of the blade and the plies are stacked on either side of the woven core to form the desired exterior surface profile. The mold is injected with a resin using a resin transfer molding process and cured. Alternatively, the composite blade can comprise a three-dimensional woven core cured with resin without the two-dimensional filament reinforced plies.